Answer:
Wavelength, 
Explanation:
We have,
Velocity of the object, 
Mass of the object, 
It is required to find the wavelength of the object. The relation between wavelength and velocity of the object is given by :

h is Planck's constant

So, the wavelength of the object is
.
D. precision. At first glance you can mark out A and B because the answers does not relate to the question. If question had said "what do you call it when the measurement is close to the actual answer" then you would have picked C. So that leaves you D. precision.
What part of it are you confused about
The answer is volume that is volume limits the precision of data obtained in an experiment .
As while pouring of the liquids, we control the volume, but it can have been off. And this could results in the wrong mole to mole ratio.Thus it limits the precision, So the answer is that volume limits the precision of data obtained in an experiment .
The high surface tension helps the paper clip - with much higher density - float on the water. The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules.
Basically it means that there is a sort of skin on the surface of water where the water molecules hold on tight together. If the conditions are right, they can hold tight enough to support your paper clip. The paperclip is not truly floating, it is being held up by the surface tension.